Tricky Superballs

Most recent answer: 01/14/2015

Q:
My daughter came home from her accelerated high school physics class today & said the teacher demonstrated that shaking a ball can cause it to lose its "bounce." She said he bounced a "super ball" type ball and then proceeded to shake it for awhile. After a time, he dropped it again & it failed to bounce -- just sat there, "thud." Is this true or was he pulling their legs?
- Mary (age old)
Park Ridge, IL USA
A:

That's not how ordinary superballs behave. They keep their bounce under any ordinary handling. I can think of two possible ways this event could have happened.

1. The teacher may be a good at sleight-of-hand, and may have replaced one ball with another during the shaking.

2. Maybe there's some source of trick balls. For example, one could make a superball with an ordinary superball outside layer but with a core made of some material that was hard when cold but melted into something gooey at around room temperature. Holding the ball in your hand while shaking could then turn the inside gooey. I haven't found evidence that anybody makes things like that, but it's possible in principle.

Mike W.

posted without vetting until Lee gets back


(published on 01/14/2015)